HSW: Heuristic Shrink-wrapping for automatically repairing solid-based CityGML LOD2 building models

The Level-of-Detail (LOD) 2 building models defined in CityGML are used widely in three-dimensional (3D) city applications. Many of these applications demand valid solid-based geometry (closed 2-manifold), which is crucial for analytical and computational purposes. However, this condition is often violated in practice because of the way LOD2...

Automatic conversion of IFC datasets to geometrically and semantically correct CityGML LOD3 buildings

Although the international standard CityGML has five levels of detail (LODs), the vast majority of available models are the coarse ones (up to LOD2, i.e. block-shaped buildings with roofs). LOD3 and LOD4 models, which contain architectural details such as balconies, windows and rooms, rarely exist because, unlike coarser LODs, their construction...

Formalisation of the level of detail in 3D city modelling

The level of detail in 3D city modelling, despite its usefulness and importance, is still an ambiguous and undefined term. It is used for the communication of how thoroughly real-world features have been acquired and modelled, as we demonstrate in this paper. Its definitions vary greatly between practitioners, standards and institutions. We...

Automatic repair of CityGML LOD2 buildings using shrink-wrapping

The LoD2 building models defined in CityGML are widely used in 3D city applications. The underlying geometry for such models is a GML solid (without interior shells), whose boundary should be a closed 2-manifold. However, this condition is often violated in practice because of the way LoD2 models are constructed and exchanged. Examples of the...

Revisiting the concept level of detail in 3D city modelling

This review paper discusses the concept of level of detail in 3D city modelling, and is a first step towards a foundation for a standardised definition. As an introduction, a few level of detail specifications, outlooks and approaches are given from the industry. The paper analyses the general uncertainties and shortcomings around the concept of...

Repair and generalization of hand-made 3D building models

Many 3D GIS applications require 3D building models with different LoD (Level of Detail) that satisfy certain quality criteria. However, because of their complexity, most detailed 3D building models available are still produced manually, which results in inevitable geometric and topological errors. These errors hinder the downstream processing...

Pattern classification approaches to matching building polygons at multiple scales

Matching of building polygons with different levels of detail is crucial in the maintenance and quality assessment of multi-representation databases. Two general problems need to be addressed in the matching process: (1) Which criteria are suitable? (2) How to effectively combine different criteria to make decisions? This paper mainly focuses on...